Printing of cellulose acetate



Patented Oct. 14, 1947 PRINTING OF CELLULOSE ACETATE FABRICS WITH ACID DYES Cyril M. Croft and Walter B. Kindle, Cumberland, Md., assignors to Celanese Corporation of America, a corporation oi Delaware No Drawing. Application October 21, 1943, Serial No. 507,155

Claims. 1

This invention relates to improvements in the printing of textile materials and relates more particularly to the direct printing oi textile materials made of or containing cellulose acetate or other organic derivative of cellulose materials.

An object of our invention is to provide an improved process for the direct printing of cellulose acetate or other organic derivative 01' cellulose materials employing acid dyestuffs.

Another object of our invention is to provide an improved process for the direct printing of cellulose acetate or other organic derivative of cellulose materials employing acid dyestufls whereby said materials may be printed in clear, bright. sharp patterns free 0! mottled effects and other faults encountered in printed materials.

A further object oi! our invention is the production of locally printed cellulose acetate or other organic derivative of cellulose material of improved appearance.

Other objects of our invention will appear hereinafter from the following detailed description.

The direct printing of textile materials containing yarns of cellulose acetate or other organic derivative of cellulose to obtain pattern effects is to some extent limited in its applications. Many dyestufl's are not suitable ior direct printing applications because they have a relatively low sublimation point and they tend to sublime when subjected to elevated temperatures, as during steaming operations. Moreover, some of these dyes are not resistant to acid fading. Other dyestuffs, for example, the vat dyestuffs, may be printed directly on to cellulose acetate textile materials in leuco form but their application is disadvantageous since they are applied in pastes which are of alkaline reaction to maintain the leuco vat dyestuil in a suitably solubillzed condition. The alkaline nature of the pastes generally eil'ects some degree of local saponlfication of the cellulose acetate material with the result that the latter may be seriously weakened. Furthermore, the application or vat dyestufis by direct printing processes requires an involved procedure. Usually, the textile material is locally printed with the printing paste after which the printed fabric is subjected to a series of operations comprising steaming, ageing, oxidation, whereby the leuco vat dyestufl' is oxidized back to the colored form and, following oxidation. the printed fabric is washed and dried. Such processes, wherein vat dyes are printed directly on to cellulose acetate textile materials, are not only involved but the printed textile materials are not always satisfactory. some vat dyestuiis have a tendency to bleed 2 oil during the steaming operation and, when applied in heavy shades, there is a tendency towards crocking. In other instances, the vat dyes mark of! on the background or an objectionable halo about the edges of the printed pattern may be observed.

We have now discovered that cellulose acetate or other organic derivative of cellulose textile materials may be printed directly in clear, bright, colored patterns which are fast to light, to scouring and to acid fading caused by atmospheric gases, without having to resort to steaming, ageing or other intermediate treatment ordinarily necessary, prior to washing and drying. These advantageous results may be obtained ii the cellulose acetate textile material is printed with a printing paste comprising an acid dyestui'i. a lower aliphatic alcohol, a, thickener, an inorganic swelling agent for the cellulose acetate material and, preferably, a lower aliphatic acid, and the printed textile material is washed directly after printing and then dried.

The acid dyestuffs which may be employed in the novel printing process of our invention are those acid dyestuffs which are normally employed for the dyeing of wool and silk and which do not possess any substantial afllnlty for cellulose acetate materials when applied by the methods usually employed for applying said acid dyestufls to the silk and wool materials. As examples of these acid dyestuffs, there may be mentioned Xylene Fast Milling Blue GL (Color Index No. 833) Polar Red G (Color Index No. 430) Artol Violet BL, Artol Green 30. Pontacyl Brilliant Blue 2R, Sulphonine Brilliant Red B (Color Index No. 430) Artol Scarlet M and Guinea Green BA Ex. Conc. (Color Index No, 666), but it will be understood, of course, that these dyestuffs are but a few of the many acid dyestuffs which may be employed.

The lower aliphatic alcohols which are suitable for use in formulating the printing paste are those alcohols which exert at least a swelling or softening action on the cellulose acetate material. While we prefer to employ ethyl alcohol in the printing paste, other alcohols such as methyl alcohol, propyl alcohols, isopropyl alcohol, nbutyl alcohol, secondary butyl alcohol, tertiary butyl alcohol, n-amyl alcohol, secondary amyl alcohol and tertiary amyl alcohol or mixtures of these alcohols may be employed. The amount of alcohol used in the printing paste will vary depending upon the alcohol or alcohols used and upon the construction of the textile material being printed. We have found that optimum results are obtained when the alcohol comprises about 30.0 to 60.0% by weight of the printing paste.

Any suitable lower aliphatic acid may be employed in the printing paste together with the alcohol. Examples of these acids are acetic acid, propionic acid and butyric acid. The acids may be employed in amounts varying from 2.0 to 4.0% on the weight of the paste, optimum results being achieved when the acid is present in amounts of from 2.0 to 3.0% by weight.

While various inorganic swelling agents for the cellulose acetate materials may be incorporated in the printing paste, we preferably employ salts of thiocyanic acid, such as, for example, ammonium thiocyanate, sodium thiocyanate and potassium thiocyanate. The most desirable results are obtained when sodium thiocyanate is em: ployed as the swelling agent. The inorganic swelling agent may be present in amounts of from 6.0 to 10.0% on the weight of the paste, but optimum results are obtained employing the swelling agent in amounts of from 6.0 to 8.0% by weight.

Any suitable thickening agent adapted to yield a thick paste which will not tend to spread or creep is satisfactory in formulating the printing pastes. Such thickening agents are, for example, gum tragacanth, hydrolyzed starch, "Supertex" gum and gum arabic. Usually, the thickening agent will comprise from 1.5 to 5.0% by weight of the printing paste.

The paste may be locally applied to the cellulose acetate textile material by any suitable means such as printing with embossed or engraved rollers, with blocks, or by stencillin operations.

After the printing paste has been applied to the textile material, the printed material is then washed directly and, following washing, may be dried. Preferably, we wash the printed material in cold water, i. e. in water at temperatures at from 25 to 30 C. Water at higher temperatures, 1. e. from 35 to 40 C., may be employed in some instances. Following the washing operation, the printed material may be soaped lightly in a bath containing from 0.2 to 0.5% by weight of soap so as to remove any excess color. The scouring or soaping bath may be employed at temperatures of 30 to 70 C.

The washed, printed fabric is then dried in any convenient manner. The material may be passed into a chamber through which air heated to a temperature of 80 to 115 C. is circulated, or the material may be passed over heated drums or cans. The dried, printed materials may then be taken up in any suitable package form, such as rolls or bolts.

By our novel process, cellulose acetate materials printed in bright, well-defined patterns may be obtained which patterns do not bleed on soaping, possess excellent i'astness to light and acid fading. and which are free from halos, flushing and marking 011'. Our novel process greatly simplifies direct printing operations since it eliminates steaming, ageing and other steps which have usually been employed in the direct printing of cellulose acetate materials.

While our invention has been described in connection with the direct printing of cellulose acetate materials, it may be employed in connection with the direct printing of materials having a basis of other organic derivatives of cellulose. Examples of such other organic derivatives of cellulose are cellulose esters, for example, cellulose propionate, cellulose butyrate, mixed esters, such as cellulose acetate-propionate and cellulose acetate-butyrate, and cellulose ethers, for exampie, ethyl cellulose and benzyl cellulose. Mixed materials containing one or more of the aforementioned cellulose derivatives together with other textile fibers may be treated in like manner in accordance with our invention. Such materials may contain, ior instance, in addition to a cellulose ester or ether, cotton, wool. silk or regenerated cellulose.

In order i'urther to illustrate our invention but without being limited thereto, the followin example is given:

Example A printing paste is prepared in the following manner. 5 parts by weight of Xylene Fast Milling Blue GL are sifted into 5.2 parts by weight of acetic acid and this mixture is added to 76 parts by weight of 05% ethyl alcohol. parts by weight of 6% sum tragacanth solution are added to the alcoholic solution and then thoroughly mixed by means of a mechanical stirrer. To this well-stirred mixture are then added 15 parts by weight of sodium thiocyanate dissolved in 25 parts by weight of water and, after thorough mixing, the paste is ready for application. The printing paste is struck oil on a printin machine on a cellulose acetate fabric and the printed fabric is then washed directly in cold water, the washing being followed by a light soaping at 60 C. with a 0.3% soap solution to remove excess color. The washed fabric is then passed through a chamber in which it is dried with air at C. The fabric is dyed in a clear bright blue pattern which possesses excellent fastness to light and acid fading. The printed fabric does not bleed on soaping and exhibits unusual fastness to washing.

A novel process for the coloration of textile materials made of or containing cellulose acetate or other organic derivative of cellulose materials by a process involving the padding of the said textile materials with an aqueous solution of a dyestufi capable of dyeing said textile materials, which solution contains a lower aliphatic alcohol and a swelling agent comprising a salt of thiocyanic acid, and immediately washing the textile material while still wet with said solution, is described in our application 8. No. 507,154 died on October 21, 1943.

It is to be understood that the foregoing detailed description is given merely by way of iilustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by Letters Patent is:

1. Process for locally dyeing textile material containing yarns of an organic derivative of cellulose, which comprises applying to said materials in a predetermined pattern a printing paste comprising an acid dyestuff. 30 to 60% by weight of a lower aliphatic alcohol, 2.0 to 4.0% by weight of a lower aliphatic acid, 6 to 10% by weight of an inorganic salt of thiocyanlc acid which is a swelling agent for the organic derivative of cellulose material and 1.5 to 5.0 by weight of a watersoluble thickener, washing the so-treated material directly after the application of the printing paste thereto, and then drying said material.

2. Process for the production of locally printed effects on textile materials containing yarn of cellulose acetate which comprises printing said material in a predetermined pattern with a printing paste comprising an acid dyestuil, 30 to 60% by weight of a lower aliphatic alcohol, 2.0 to 4.0% by weight of a lower aliphatic acid, 6 to 10% by weight of an inorganic salt of thlocyanic acid which is a swelling agent for the cellulose acetate material and 1.5 to 5.0% by weight of a water-soluble thickener, washing the printed material directly after printing, and then drying the printed material.

3. Process for the production of locally printed effects on textile materials containing yarns o1 cellulose acetate, which comprises printing said materials in a predetermined pattern with a printing paste comprising an acid dyestufi, from 30 to 60% by weight of ethyl alcohol, from 2 to 4% by weight of acetic acid, from 6 to 10% by weight of sodium thiocyanate and from 1.5 to 5.0% by weight a water-soluble thickener, washing the printed textile material directly after printing, and then drying the printed material.

4. Process for the production of locally printed eflects on textile materials containing yarns of cellulose acetate, which comprises printing said materials in a predetermined pattern with a printing past comprising an acid dyestufl, from 30 to 60% by weight of ethyl alcohol, from 2 to 4% by weight oi acetic acid, from 6 to by weight of sodium thlocyanate and from 1.5 to 5.0% by weight of a water-soluble thickener, washing the printed textile material in cold water directly after printing, and then drying the printed material.

5. Process tor the production of locally printed eflects on textile materials containing yarns of cellulose acetate. which comprises printing said material in a predetermined pattern with a print- 6 ing paste comprising an acid dyestufl, from 30 to by weight of ethyl alcohol, from 2 to 4% by weight of acetic acid, from 6 to 10% by weight 0! sodium thiocyanate and from 1.5 to 5.0% by weight of a water-soluble thickener, washing the printed textile material in cold water directly after printing, soaping lightly to remove excess color, and then drying the printed material.

CYRH. M. CROFT.

WALTER. H. HINDLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,398,357 Briggs Nov. 29, 1921 1,517,581 Rabe Dec. 2, 1924 1,792,152 Ellis Feb. 10, 1931 1,968,819 Dreyfus Aug. 7, 1994 1,968,856 Rivat Aug. 7, 1934 2,079,604 Dickie May 11, 1937 2,248,048 Allan July 9, 1941 2,259,515 Croft Oct. 21, 1941 2,292,433 Croft Aug. 11, 1942 FOREIGN PATENTS Number Country Date 297,848 Great Britain Oct. 24, 1929 362,721 France Apr. 12, 1908 500,980 Great Britain Feb. 17, 1939 528,450 Great Britain Oct. 30, 1940 Certificate of Correction Patent N 0. 2,428,836.

October 14, 1947.

CYRIL M. CROFT ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 4, line 65, claim 1, for 1.5 to 5.0 by weight read 1.5 to 5.0% by weight; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 20th day of January, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

10% by weight of an inorganic salt of thlocyanic acid which is a swelling agent for the cellulose acetate material and 1.5 to 5.0% by weight of a water-soluble thickener, washing the printed material directly after printing, and then drying the printed material.

3. Process for the production of locally printed effects on textile materials containing yarns o1 cellulose acetate, which comprises printing said materials in a predetermined pattern with a printing paste comprising an acid dyestufi, from 30 to 60% by weight of ethyl alcohol, from 2 to 4% by weight of acetic acid, from 6 to 10% by weight of sodium thiocyanate and from 1.5 to 5.0% by weight a water-soluble thickener, washing the printed textile material directly after printing, and then drying the printed material.

4. Process for the production of locally printed eflects on textile materials containing yarns of cellulose acetate, which comprises printing said materials in a predetermined pattern with a printing past comprising an acid dyestufl, from 30 to 60% by weight of ethyl alcohol, from 2 to 4% by weight oi acetic acid, from 6 to by weight of sodium thlocyanate and from 1.5 to 5.0% by weight of a water-soluble thickener, washing the printed textile material in cold water directly after printing, and then drying the printed material.

5. Process tor the production of locally printed eflects on textile materials containing yarns of cellulose acetate. which comprises printing said material in a predetermined pattern with a print- 6 ing paste comprising an acid dyestufl, from 30 to by weight of ethyl alcohol, from 2 to 4% by weight of acetic acid, from 6 to 10% by weight 0! sodium thiocyanate and from 1.5 to 5.0% by weight of a water-soluble thickener, washing the printed textile material in cold water directly after printing, soaping lightly to remove excess color, and then drying the printed material.

CYRH. M. CROFT.

WALTER. H. HINDLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,398,357 Briggs Nov. 29, 1921 1,517,581 Rabe Dec. 2, 1924 1,792,152 Ellis Feb. 10, 1931 1,968,819 Dreyfus Aug. 7, 1994 1,968,856 Rivat Aug. 7, 1934 2,079,604 Dickie May 11, 1937 2,248,048 Allan July 9, 1941 2,259,515 Croft Oct. 21, 1941 2,292,433 Croft Aug. 11, 1942 FOREIGN PATENTS Number Country Date 297,848 Great Britain Oct. 24, 1929 362,721 France Apr. 12, 1908 500,980 Great Britain Feb. 17, 1939 528,450 Great Britain Oct. 30, 1940 Certificate of Correction Patent N 0. 2,428,836.

October 14, 1947.

CYRIL M. CROFT ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 4, line 65, claim 1, for 1.5 to 5.0 by weight read 1.5 to 5.0% by weight; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 20th day of January, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

